Final Diagnosis -- Rhabdoid Tumor of the Thyroid

Malignant rhabdoid tumors originally described as renal neoplasms in children, have since been described in extrarenal sites [1, 2]. In 1998 Chetty and Govender reported three cases of follicular thyroid carcinoma with rhabdoid phenotype [3]. Subsequently, four additional cases have been reported [4-6]. The patients ranged in age from 42 to 67 years and 6 of 7 were females. Rhabdoid thyroid carcinomas are aggressive, with metastases reported in six of the seven cases and death from disease in five of six patients.

The tumor in this case was composed of 95% malignant rhabdoid cells. As previously described in similar cases, this tumor had an aggressive clinical course. This case is only the second reported case of rhabdoid thyroid carcinoma occurring in the setting of papillary thyroid carcinoma and only the second one reported in a male.